Ms. Cindy Ott-Jones Page 2 I. Proposed Action and Action Area The proposed action in this consultation includes a variety of management actions for exotic, invasive, threatened, and endangered species on Federal land. The National Park Service (NPS) is proposing to enhance habitat for select federally listed species and manage exotic biota and trespass livestock in Big Bend National Park (BBNP). Located in Brewster County in west Texas along the Rio Grande / Río Bravo del Norte (Rio Grande), BBNP totals about 801,000 acres (ac) or 1,252 miles2 including inholdings. About 1,214 miles2 are Federal Land (Jameson 2010). Notable aspects of BBNP are: the broad diversity of plants and animals, its geologic history, the Chisos Mountains with panoramic views of exemplary Chihuahuan desert, and the Rio Grande with its scenic canyons and riparian areas. For a detailed description of BBNP, please see section 4.0 of the BA. The NPS has prepared three documents for BBNP: Exotic Plant Management Plan, Exotic Animal Management Plan, and the Trespass Livestock Management Plan, collectively referred to as Exotic Species Management Plans. Additionally, the NPS has responsibilities for managing federally listed threatened and endangered species and their habitats in BBNP. The planned activities are detailed in the May 2015 BA and the Exotic Species Management Plan. The NPS has provided its determinations that the proposed action may adversely affect the following federally threatened /endangered species: Common Name Scientific Name Federal Status bunched cory cactus Coryphantha ramillosa Threatened Echinocereus chisosensis var. Chisos hedgehog cactus Threatened chisoensis Lloyd's mariposa cactus Echinomastus mariposensis Threatened Big Bend gambusia Gambusia gaigei Endangered black-capped vireo Vireo atricapilla Endangered Threatened for western yellow-billed cuckoo Coccyzus americanus distinct population segment (DPS) Ms. Cindy Ott-Jones Page 3 The NPS determined that the proposed action will have “no effect” on a group of federally listed candidate, threatened, or endangered species known from BBNP. Additionally, the NPS determined that the proposed action may affect; but, is not likely to adversely affect: (1) the endangered Mexican long-nosed bat (Leptonycteris nivalis), (2) the endangered southwestern willow flycatcher (Empidonax traillii extimus), (3) the threatened Mexican spotted owl (Strix occidentalis lucida), (4) the non-essential experimental population of Rio Grande silvery minnow (Hybognathus amarus), and (5) the proposed critical habitat of the yellow-billed cuckoo as the effects of the proposed management actions are considered insignificant, discountable, or completely beneficial to the proposed critical habitat. Based on the description of the proposed action with conservation measures in the BA, the Service concurs with NPS’s determinations. The term “action area” means all areas to be affected directly or indirectly by the Federal action and not merely the immediate area involved in the action. The BA describes the action area as generally the BBNP boundary; but, acknowledges that some management actions, e.g., generating turbidity in the Rio Grande /Río Bravo del Norte, would potentially have some effects outside of the BBNP boundary. The action area for this consultation includes all of the BBNP and nearby areas that may be affected by management actions (see Figure 7 of BA). We consider the action area to be BBNP and an area within 100 meters of the National Park boundary, which should capture the direct and indirect effects of the proposed action. The proposed action has four management parts: exotic plants, exotic animals, trespass livestock, and habitat enhancement for select species, such as the Big Bend gambusia. The BA and individual management plans describe the activities planned to monitor and control impacts of exotic species and trespass livestock. Activities to reduce and control exotic plants and animals in BBNP will use an Integrated Pest Management (IPM) approach. Management of Plants The highest management priority plant species in BBNP are: African buffelgrass (Cenchrus ciliaris), Lehmann’s lovegrass (Eragrostis lehmanniana), tamarisk (salt cedar) (Tamarix spp.), giant reed (Arundo donax), King Ranch (K-R) bluestem (Bothriochloa ischaemum var. songarica), Kleberg bluestem (Dichanthium annulatum), and Malta star-thistle (Centaurea melitensis). The treatment methods for exotic plants are detailed in the BA Tables 1 and 2 and include: (1) prescribed fire, (2) mechanical, (3) cultural, (4) chemical treatments, and (5) biological control agents. The BBNP Fire Management Plan (NPS 2005) provides the framework for making fire-related decisions – responses and includes steps for initial action on ignitions pursuant to the goals and objectives of the plan. Ms. Cindy Ott-Jones Page 4 Mechanical (manual) treatments involve digging with shovels or hoes, pulling /cutting by hand, chainsaws, and cutting of the cambium with a machete followed by application of gauze with herbicide. Cultural control involves re-vegetating, irrigating, and/or fertilizing to establish healthy native ground cover, resistant to invasive plants. Chemical treatments would include coordination with Regional and National IPM Coordinators and would comply with the NPS Director’s Order-77. The methods of herbicide application would depend on the target species and range from hand application with non-powered sprayers to battery- or gasoline-powered sprayers mounted in trailers, trucks, or boats, to aerial spraying (e.g., for larger stands of giant reed in the floodplain). A significant number of the proposed treatment areas for exotic plants are roadside and developed areas. A few of the roadside areas may be occupied by endangered cactus species. Management of emergent macrophytes in and near Big Bend gambusia habitat (ponds) may involve a combination of mechanical and chemical approaches. Management of Animals other than Livestock The highest management priority animal species in BBNP parkwide are aoudads (Barbary sheep) (Ammotragus levia) and feral hogs (Sus scrofa). Depending on circumstances, localized parts of the BBNP may be controlled for the following species if their impacts reach a priority (action) threshold: nutria (Myocastor coypu) red-eared slider (Trachemys elegans) bullfrog (Rana catesbiana) eastern green tree frog (Hyla cineria) blue tilapia (Oreochromis aureus) red imported fire ants (RIFA) (Solenopsis invicta) A matrix of action thresholds, areas for treatment and treatment methods is presented in the BA’s Table 3. Figure 3 of the BA shows the initial priority management area for nutria, bullfrog, and green tree frog. The treatment methods for aoudads and feral hogs include shooting (aerial- and ground-based), trapping, fencing, and use of Judas (Lead) animals. Currently no treatment methods have been identified for blue tilapia and additional study is needed. To manage RIFA, surveys, study, and monitoring would typically precede control. Chemical approaches targeting RIFA would be used in a limited part of the Chisos Basin Campground and vicinity. Trespass Livestock Management Trespass livestock involves burros, horses, and cattle that enter BBNP from adjacent properties in Mexico and U.S. The livestock damage the park’s natural resources and potentially spread Ms. Cindy Ott-Jones Page 5 diseases to other livestock, wildlife, and humans. Livestock may be: (1) returned to the owner (potentially with penalty), (2) roundup by mounted wranglers, (3) roundup assisted by helicopters, (4) subject to aerial capture and transport, (5) managed by fencing, (6) trapped, or (7) managed as Abandoned and Unclaimed Property pursuant to Federal regulations. Figure 4 in the BA shows the four management zones for trespass livestock in BBNP. Management of trespass livestock reduces the damage livestock pose to springs, water quality, soil conservation, and vegetation. Management of Special Status Species The BBNP’s goals include improvement of habitats for southwestern willow flycatchers (Empidonax traillii extimus), yellow billed cuckoo (Coccyzus americanus), and black-capped vireos (Vireo atricapilla). The primary activity planned for aquatic species in this category is to ensure the habitat of the Big Bend gambusia is not adversely reduced by an overabundance of native cattails (Typha spp.), native reeds (Phragmites spp.), and non-native giant reed (Arundo donax). Physical – mechanical removal (e.g., with machetes) of cattails may occur in and near aquatic habitat occupied by Big Bend gambusia. Additionally, careful application of the herbicide imazapyr may be used to control these emergent macrophytes. Imazapyr (Arsenal®) has a low potential toxicity and is not known to be toxic at environmentally relevant concentrations to fish, livestock, or humans. However, any herbicidal treatments in Big Bend gambusia habitat will be done incrementally (treating less than a third of a pond annually) to avoid oxygen depletion from decomposing plant material. The removal of emergent vegetation in Pond No. 1 and the Hubbs Refuge is expected to double or triple the amount of suitable Big Bend gambusia habitat by restoring more open water. Conservation Measures Section 3.1.6 of the BA describes the varied ways in which the management plans: (1) avoid, reduce, or eliminate adverse effects to listed species and (2) benefit federally listed species and their habitats. These include: avoiding and reducing the adverse effects of vehicles; minimizing